This invention relates to a calculator having a plurality of definable keys each of which is given a specific definition as an input key for an instruction and a constant through execution of a specific definition instruction. More particularly, the present invention pertains to an electronic calculator wherein a definition instruction distingushable from the first named definition instructions is set up and said plurality of keys are given specific definitions as input keys which are useful in introducing different pieces of information by depression of a conventional shift key.
For the conventional programmable calculator, there is provided a keyboard with a number of alphanumeric keys, a common shift key and other kinds of keys. By depressing the shift key each of input keys is given no more than two definitions. However, this requires simultaneous actuations of the input and shift keys and complexity of key actuations.